The perfect roast potato...

how do you cook yours?
I usually just peel, chop and fling in the oven at the same time as whatever meat I'm roasting. Most of the time they come out very tasty, but sometimes they're a bit lacking that certain something.
So, how do you get crispy outside, fluffy inside, perfect roast potatoes?

The right potato to begin with, then parboil for 10 mins or so, drain and return to pan, shake vigorously until surface of potatoes is all roughed up.
Place in roasting pan with goose or duck fat, I like to sprinkle polenta over them at this point and place in hot oven for about an hour turning once.
Some people insist that the potatoes should be put into hot fat but cold has always worked well for me.

My friend suggested tossing in couscous. I tried it tonight with some wedges and it was really
good. I did toss par boiled wedges in oil first and then couscous. Normally I do the Jamie Olivier type of parboil and rough the edges before putting into hot olive oil. That works too.

I know it's cheating but I bought some of those M&S roast potato sprinkles for Christmas dinner and I have to say they were the best roasties I've ever done.
Was cooking for 10 and everyone commented on how nice they were. To be honest I think the sprinkes are just herby semolina (which I have also used) but I will definately be buying again.